The increasing demand for wireless services has placed a premium on the efficient use of RF spectrum. Many wireless protocols are designed around the concept that frequencies and channels may be reused by properly designed and managed systems. Re-use of spectrum creates the potential for signals of one system to interfere with signals of another.
Devices that use wireless services can also be required to evaluate various signals that are present at a particular location in order to detect and identify them, as well as find a piece of RF spectrum that is available for communication. Wireless devices may use various techniques, including spectrum analysis, to accomplish this task.
A multi-carrier signal is typically comprised of many equidistant sub-carriers. By way of illustration and not by way of limitation, a multi-carrier signal may include Orthogonal Frequency-Division Multiplex (OFDM) signals such as DAB, DVB-T/H, Wi-Fi (802.11a/g/n), WiMAX, LTE, and Discrete Multi Tone (DMT) signals such as ADSL G.992.1. Different multi-carrier signals typically have different sub-carrier distances and thus different spectrum periods within their bandwidth. Different multi-carrier signals also have different bandwidths. Detection of the signals can be done with prior knowledge of signal parameters, or without knowing them (blind detection).
Sensing whether a particular multi-carrier signal is present in a spectrum sample may be useful for RF network planning, RF network interference analysis, dynamic spectrum access (e.g. in cognitive radio), designing a wireless device capable of using the particular multi-carrier signal, and audio signal analysis.